Refrigerating or Freezing Apparatus with Vacuum Compartment

ABSTRACT

A refrigerator or freezer apparatus comprising: a cabinet ( 1 ) at least a compartment ( 2,3 ) to store food, a box ( 5 ) firmly lodged in said cabinet and closable in a vacuum-tight manner, a drawer ( 6 ) apt to be extracted and inserted in said box, a vacuum pump ( 7 ) connected to said box in the back side of it, a vacuum valve ( 13 ) able to selectively equalise the internal pressure in said box, wherein it comprises locking means, and specially a tiltable handle in the front side of said drawer, able to connect or disconnect said drawer to/from said box; said vacuum valve and/or said vacuum pump are operated by the tilting movement of said handle or by the closing movement of said drawer ( 6 ).

TECHNICAL FIELD

The present invention refers to a refrigerator and/or a freezer providedwith a compartment in which vacuum is produced by means of a vacuumpump.

BACKGROUND

It is well known that the cold preservation of foods under vacuum offersconsiderable advantages. In particular, it enables such foods to be keptin a refrigerator or the like with considerably slowed degradation. Withparticular reference to household refrigerators, various methods havealready been proposed for providing in the refrigerator a compartmenthaving its own door and connected to a vacuum pump (see, for example,FR-A-1 377 844).

In the prior art it is generally known that in a refrigerationcompartment of a refrigerator, freezer or the like there is provided acontainer closable in a vacuum-tight manner and able to be moved withinsaid compartment, said container being provided with a pipe throughwhich the vacuum is produced and which is arranged to cooperate with acounter-pipe provided in the usual cabinet of the refrigerator or thelike and opening into a wall of said compartment, said counter-pipebeing connected to the vacuum pump, at least one of the cooperating endsof said pipes comprising a hollow elastic element arranged to form aseal against the other end.

This method results in various advantages such as considerableconstructional simplicity of the refrigerator, low production cost, easeof access to the compartment in which the vacuum is provided, and easeof its cleaning.

However, such a construction has various drawbacks, such as the possiblyimperfect closure of the lid of the container during its reinsertioninto the refrigeration compartment after being extracted from it, andpossibly imperfect connection between the pipe associated with thecontainer and the relative counter-pipe.

From U.S. Pat. No. 2,119,320 a refrigerator is disclosed with means formaintaining a partial vacuum in the food compartment including a suctionpump to draw air out the same compartment and also to draw off odours;means are comprised which are automatic in their operation so that whenthe refrigerator is opened they will permit air to rush into the foodcompartment and raise the pressure therein to atmospheric pressure.

However, the whole food compartment, and not only a separate container,different from said compartment, is subjected to the vacuum operation sothat, if the user wishes to store the food in the refrigeratorcompartment without subjecting it to the vacuum, this way of operationis impossible to be achieved. Furthermore the handle to open the door isassociated to a mechanism, to let the air into the compartment, which iscomplicated and burdensome.

In US 2002/0083724 A1 a food storage and preservation system isdisclosed showing a plurality of food storage containers each havingrelated door, related vacuum associated devices, and a centralised airtreatment module comprising a vacuum pump and switch sensor thatactivates when a container door opens or closes; this food system iscreated to stay both inside or outside of a refrigerator.

Then it is not functionally optimised to work inside a refrigeratorcompartment only; furthermore it is expandable and modular, while saidfeatures do require technical and operating features that are notacceptable in a refrigerator apparatus for household use.

From U.S. Pat. No. 6,090,422 a refrigerator is known which comprises avacuum cabinet, which includes a vacuum compartment and an open topdrawer in the vacuum compartment. The suggested solution is basicallywell known in the art, with the adding of a timer, operated by the doorclosing, and automatically controlling the vacuum pump operation. Saidrefrigerator suffer the drawback that the venting means to theatmosphere comprise a pushing valve that has to be operated manuallyeach time the vacuum compartment is pulled out; this operation may beuneasy and also may be often forgotten, thus not making the vacuumcompartment user friendly.

From EP 0440296 a refrigerator is known which comprises a vacuum cabinetwhich includes a vacuum compartment and a drawer in the vacuumcompartment, said compartment being associated to a related top lid;even in this case the vacuum compartment is complicated both to beproduced and to be operated, as the lid has to be automaticallydisengaged while the drawer is pulled-out, and remains inside therefrigeration compartment, while the drawer stays outside it. All thatimplies complicated mechanical means as especially showed in the FIGS. 3and 4 of the relevant patent.

An object of the present invention is therefore to provide arefrigerator or the like comprising a movable container internally undervacuum, which obviates the drawbacks of known constructions. Aparticular object is to provide a refrigerator with a vacuum containertype where the operation of the vacuum valve is controlled by the samehandle used to open/close the door.

A further object is to provide a refrigerator of the aforesaid type,where the same handle is also used to operate the vacuum pump accordingto the same handle operation. Another object of this invention is toarrange such type of refrigerator so as, alternatively from the justgiven solutions, said vacuum pump and/or said vacuum valve are operatedby the closing movement of said drawer into said box.

According to the present invention, these aims are reached in arefrigerator or a freezer apparatus having the features disclosed in theappended claim 1.

DESCRIPTION OF DRAWINGS

Further advantageous features will become apparent and may be readilyunderstood by the following description, which is given below by mereway of not-limiting example with reference to the accompanying drawings,in which:

FIG. 1 is a vertical side section through a domestic refrigeratorconstructed in accordance with a first embodiment of the invention,

FIG. 2 is a corresponding side section of a similar refrigeratoraccording to a second embodiment of the invention,

FIG. 3 is a perspective partial view of the inner part of a refrigeratoraccording to the invention, in a first operative condition,

FIG. 4 is a perspective partial view of the inner part of a refrigeratoraccording to the invention, in a second operative condition,

FIGS. 5 and 6 are vertical side partial views of a drawer according to afirst embodiment of the invention, in respective different stage of itsuse,

FIGS. 7 and 8 are vertical side partial views of a drawer according to asecond embodiment of the invention, in respective different stage of itsuse,

FIG. 9 is a schematic view of a refrigerator according to a furtherembodiment of the invention,

FIGS. 10 and 11 are schematic enlarged views of a particular feature ofthe refrigerator according to the embodiment shown in FIG. 9, in twodifferent operative conditions, respectively.

DESCRIPTION OF AN ILLUSTRATIVE EMBODIMENT

With reference to FIGS. 1 and 2, respectively, a refrigerator or freezercomprises a cabinet 1 containing a refrigeration compartment 2 and afreezer compartment 3, each provided with its closure door 4 and 4 a,respectively. The refrigerator is also provided with a box 5 wherein adrawer 6 that can be inserted or extracted.

A vacuum pump 7, operated by an electric motor, not shown, andpositioned in the back lower side of said cabinet 1, is connected tosaid box through a pipe 8 extending through a back wall 9 of said box 5.To said vacuum pump is associated a vacuum valve 13, normally consistingof a regulated pressure valve or similar well known in the art, whosefunction and structure are not further explained, whereas the operationof this valve 13 will be described in detail hereinafter.

The box 5 is maintained in known manner at a specified temperature,being substantially lodged into said refrigerated compartment 2 or beingin some way externally lapped by a flow of cold air. Said box 5 can beopened directly from the outside, and it can be accessible withoutopening the compartment closure door 4, as exemplified in FIG. 2; as analternative to this “drawer-type” embodiment, the whole box 5 may befully contained in the compartment 2, so that if the user wants to openit, he has to first open the external door 4 b and then he can act on abox closing wall 10 (FIG. 1) of the drawer 6.

The front closing wall 10 protrudes from the general contour of thedrawer 6, and the dimensions and arrangement of the box 5, the drawer 6and the front closing wall 10 thereof relative to each other are soselected as to ensure that said drawer is capable of being fullyinserted in said box up to the point at which the back surface 12 ofsaid front closing wall 10 comes into abutting against the peripheraledge 11 of said box 5 (FIG. 5-8), thereby closing the latter in avacuum-tight manner.

As shown in FIGS. 5 and 7, the actual vacuum-tightness can be ensured byarranging appropriate sealing means 14 either against and along theperipheral edge 11 of the box 5 or, alternatively, in the mostappropriate position according to the most fitting pattern of the backsurface 12 of the front closing wall 10. In order to close and/or opensaid drawer by separating it from said box 5, said front closing wall 10is provided with a pivotally turning handle 15 which is hinged on twocorresponding hinging pins 16 arranged on the two opposite, verticalsides of said front closing wall 10. As a result, this handle 15 is madecapable of performing a raising and lowering movement about thehorizontal axis passing through said two pins 16, as illustratedsymbolically in FIGS. 3 and 4.

The handle 15 is further provided, at its inner ends, with tworespective extension links 17 (FIG. 5-8), which are curved in suchmanner as described in greater detail below. On the two sidewalls ofsaid box 5, there are further arranged two engagement means, which arerepresented by two projections 18 in the example being considered. Theshapes, dimensions and arrangement of the above noted elements relativeto each other are so selected as to ensure that, upon the drawer 6having been pushed into its closed position, wherein it is preferablypushed with the use of said handle 15 on the front side thereof, bysubsequently turning the same handle 15 downwards said extension links17 are caused to engage the respective projections 18 in such a manneras to retain said front wall 10 in the closing position thereof (seeFIGS. 6 and 8).

Said extensions 17 will of course engage the corresponding members 18 byestablishing a kind of semi-elastic, loosable link, so that it will bepossible for this link to be released for pulling out and opening thedrawer by simply lifting said handle 15, i.e. turning it upwards, so asto release said extension links 17 from the respective projections 18.

When said drawer 6 and the respective handle 15 are in the closedposition thereof, the same drawer is separated in a tightly sealedmanner from the outside ambient, so that a vacuum can be generatedinside it using generally known means. However, when the drawer has forany reason to be opened, i.e. pulled out from its closed position, theneed most obviously arises for the internal pressure of the drawer to befirst equalised to the pressure of the outside ambient. To this purpose,different solutions have been proposed and used in the prior art, all ofwhich share the fact that said restoration of the inner pressure toambient value is performed by the actuation of a specially providedcontrol device.

The need for such a special control device to be used gives rise to acouple of major drawbacks: the first one of these drawbacks isrepresented by the same air release device, which may in fact be subjectto deterioration and, as a result, may eventually constitute anundesired route for the air to pass through, while the second one ofsaid drawbacks certainly lies in the fact that, before the drawer can bepulled out and opened, the need arises for said additional manipulationto be performed in view of operating said air release control device.

In view of doing away with both such major drawbacks, an improvedembodiment of the present invention provides for said vacuum valve 13 tobe so arranged as to be capable of being acted upon in such a mannerthat, as soon as the drawer 6 starts to be opened, and therefore as soonas the handle 15 is lifted, the resulting rotary movement of saidextension links 17 causes the latter to act on an electric switch 19,which is preferably located on the outside of said box 5 in a positionclose to the respective projections 18.

Said electric switch 19 is connected via an appropriate link-up 20 tosaid vacuum valve 13, in such a manner that, as soon as said handle isoperated, the release movement of the members 17 and 18 to disengagefrom each other is preceded by the actuation of said switch 19. Thiscauses said vacuum valve 13 to open, so as to almost instantly restorethe internal pressure of the drawer to the ambient value. In this way,the continued turning movement of the handle eventually enables thedrawer to be released from its box 5.

Furthermore, the switch 19 is also connected to said vacuum pump 7 viaappropriate electrical connections (of any known kind and not shown).Upon the drawer having been so released from the box, it can then bepulled out by simply pulling it with the help of the handle 15.

Closing the drawer and re-establishing a vacuum inside it are on thecontrary performed as follows: the drawer is inserted all the way intoits box 5 and, immediately thereafter, the handle 15 is turned down,thereby achieving the following results:

-   -   the drawer is blocked in position in the box 5,    -   the extension link 17 acts on the switch 19,    -   the latter, via said connection 20, causes the vacuum valve to        enable the vacuum-tightness of the internal volume of the drawer        to be restored,    -   the same switch 19 outputs an appropriate signal to the vacuum        pump 7, so as to cause it to switch on to create vacuum inside        the box 5 and, as a result, inside the drawer 6.

In this manner, through the sole and simple operation of the handle 15it is possible for both:

-   -   the pressure inside the box 5 to be equalised prior to the        drawer being pulled out, and    -   the drawer itself to be closed in a tightly sealed manner and,        at the same time, the vacuum pump 7 to be switched on        immediately upon said drawer being inserted in the box 5.

The above illustrated solutions concerning the electric switch 19 mayalso be embodied in different forms and manners. In fact, with referenceto FIGS. 7 and 8, instead of the switch 19 arranged laterally on the box5, use can be made of an equivalent switch 19A arranged again on theoutside of the same box 5, namely so as to project from the front edge21 of said box towards the back surface 12 of said front closing wall10. This switch must in this case be so positioned and oriented as toenable it to be actuated by the same front closing wall 12 of the drawer6 when the latter is pushed into closing. The operation of this switchand the connections thereof with the vacuum valve and the vacuum pumpare the same as the ones that have been just described above, since theyare in both cases arranged and adapted to detect the final phase of theclosing movement and the initial phase of the opening movement of thedrawer relative to its containment box 5, so that they shall not bedescribed here any further.

Of course, it is apparent that the above described solutions may befurther adjusted; for instance, instead of a horizontal handle 15, therecan be installed and used a vertical handle on condition thatprojections 18 are appropriately positioned on the box 5.

The configuration that is generally represented and illustrated in thisspecification, and which makes use of a box 5 that is firmly mountedinside the cold storage compartment 2 of a refrigeration apparatus, aswell as a drawer 6 that is capable of being pulled out of said box,allows for a further improvement to be implemented, which certainlyproves as being particularly advantageous under certain circumstances.It may in fact happen that certain kinds of foodstuffs being kept storedfor prolonged periods of time may give out gases (e.g. carbon dioxide)or, anyway, odours and even transudation liquids, which, apart frombeing anyway unpleasant, generally make the storage and preservationconditions of the same foodstuffs worse and far less favourable. Theseoccurrences may further become considerably more marked in the case thatthe same foodstuffs generating such emissions is being kept in anambient under controlled vacuum conditions.

In other words, if such foodstuffs are kept stored under vacuumconditions for a certain period of time, gases are likely to begenerated in the same storage ambient, which would be better removedtherefrom.

The above-cited improvement takes care of this by providing for saidregulated pressure valve 13 (FIG. 1) to be in fact connected to controlmeans (of any known kind, not shown), which is adapted to periodicallyenergise said valve 13 and said vacuum pump 7, so as to cause them tooperate according to the following cycle:

-   -   1. At a pre-determined time elapses, the regulated pressure        valve 13 is switched on to open, thereby allowing ambient air to        flow into said box 5 and eliminating the vacuum therein; during        this time the vacuum pump 7 is switched off, i.e. does not        operate    -   2. Next, and preferably after a short pre-determinable time, the        regulated pressure valve 13 is operated so as to close the        passage to the outside ambient and connect the interior of the        box 5 with the vacuum pump 7    -   3. At this point, the vacuum pump is switched on to operate, so        as to re-establish vacuum conditions inside the box 5.

It can be readily appreciated that, by performing the above cycleperiodically, the box 5 is ventilated and, in particular, the gasespossibly existing therein are removed periodically, owing to them mixingup with the inflow ambient air, which is in turn removed from said box 5by said vacuum pump 7 soon thereafter.

The manner in which the various parts and members involved and therelated connections may be made and implemented is fully apparent to andwithin the abilities of those skilled in the art, so that it shall notbe described here any further. In particular, control means 30 (FIG. 2)may be advantageously integrated with more general control andregulation means that are already present in the refrigerationapparatus. Furthermore, said regulated pressure valve 13 may be mosteasily implemented with the use of a simple three-way valve of a kindthat is well known as such in the art.

A refrigerating apparatus as described allows further advantageousimprovements; in the facts even if the positive effect on food storageunder vacuum condition is well known, yet the vacuum devices are notusually available in the domestic environment; so the food producersdirectly provide their food products properly packaged under vacuumconditions. These kind of packaging consist of hermetic soft bags,mainly made of plastic sheets, from which air is withdrawn and soonafter they are sealed and closed.

The embodiment of the present invention offers the possibility ofarranging vacuum bag packages directly at home. This improvement isobtained as follows:

A dispenser 41 is pivotally mounted on the external wall 40 of therefrigerating apparatus according to the instant invention; saiddispenser 41 consists of a prolonged member, internally provided with anhollow duct 42, opened at the outside with a mouth 43, and openedtowards said wall 40 with a mouth 44 (FIGS. 9 and 10).

Close to said mouth 44, said dispenser is provided with a hinge elementthat connects said dispenser with said external wall 40 in a rotatingway. On this external wall 40 is provided a second duct 46 connected toa part of said apparatus that is normally kept under vacuum condition;this part may be, e.g. the same box 5 or a stretch of said duct 8connected to said vacuum pump 7, or even to a buffer tank 25 that willbe better described hereunder.

In any case said second duct 46 is apt to intake the outside air fromits external mouth 47, that, on the outside, is associated to a gasket49. The described elements are sized and reciprocally arranged so that:

-   -   under still conditions (FIG. 10) the dispenser 41 is rotated        downwards around the hinge, and in this position its pivotal        end, close to said mouth 44, closes the faced mouth 47 of said        second conduit 46, even for the effect of said gasket 49 pressed        by the end of the dispenser;    -   under working condition (FIG. 11) the side 50 is turned away and        said two conduits 42 and 46 are placed into alignment so that        the mouth 44 of the dispenser 41 is brought in front of said        mouth 47 of the second conduit 46; therefore said two conduits        are automatically connected, so implementing a unique open way.

At this point the operation will be apparent to the person skilled inthe art. When the dispenser is pushed downwards, there is no connectionbetween the conduits 42 and 46, and therefore there is no air suction.When the user wants to create vacuum conditions in a bag containing food(not shown in the figures), he has to lift the dispenser by rotating itaround the hinge element (to an extent not enough to make said mouth 47of said second conduit 46 open into said first conduit 42), then the bagopening has to be applied around the external mouth 43 of the dispenser,then said opening is clasped and closed to said mouth 43 so that any airpassage from the dispenser to outside is prevented. Afterwards, thedispenser is still lifted in such a way that said conduits 42 and 46 areput into alignment so that said mouth 47 of said second conduit 46 isopen into said first conduit 42.

As a consequence the air contained in said bag is at once sucked intosaid first conduit 42 and second conduit 46, from which it is evacuatedaway in the remaining portion of said conduit 46, till the vacuumcondition in the bag is achieved. The operation continues byhermetically closing the bag opening in a position where the dispenseris not involved, by pushing down the dispenser, and finally by takingaway the bag.

It will be understood by a person skilled in the art to replace thehinge-mounted dispenser with another kind of dispenser (not disclosed inany drawing) in order to achieve a vacuum-creating feature for the user.Such a dispenser may for instance comprise a mouthpiece which could beoperated in a vertical direction in parallel with the direction of theairflow creating the vacuum. The mouthpiece is preferably spring loadedto keep the mouthpiece in a normally closing position. Moving themouthpiece vertically will open the mouth 47 in order for air to flow.Preferably, said alternative dispenser could both replace the dispenserillustrated in FIGS. 10 and 11 and also the container for collectingliquid described below in order to create a more user-friendly solution.The gravity will also in this solution create the liquid-air separation.

In order to avoid that incidental liquids, as exudates, juices, etc. bewithdrawn from said food bag into said second conduit 46, that would bedangerous for the hygienics of the whole apparatus, and for the vacuumpump safety, a further improvement is in described hereinafter. In theback face of said wall 40 a trap for liquid is provided, that isbasically formed by:

-   -   a container 51 provided with a first opening 52 and a second        opening 53,    -   said first opening 52 being connected to the portion 46 a of        said second conduct 46 turned to said wall 40,    -   said second opening 53 being connected to the portion 46 b of        said second conduct 46 turned to the opposite way,    -   said first opening 52 being placed at a slightly higher position        (level) than the second opening 53.

It is then apparent that said trap is able to collect the liquidsincidentally entering through said portion 46 a, as they would fall bygravity on the bottom of said container 51, so preventing them fromentering into the second conduit 46 b and from it to the vacuum pump 7and even to the box 5. Of course said container is provided with means,not shown, that, when needed, can permit to open the same container andto evacuate the liquids possibly there stagnating.

When the liquids are not taken away in the right time, it is possiblethat the liquid level will rise until it reaches the level of saidsecond opening 53; in order to avoid that said liquid enters into saidportion 46 b, a ball valve 55 is provided close to the opening 53. Saidvalve is arranged in such a way that, when the liquid level 54approaches the level of said second opening 53, the ball valve 55 willfloat and rise until it will close said opening 53, so achieving therequested safety.

It is also understood that appropriate means 56 are provided that aresuitable to lead said ball valve exactly in front and against saidsecond opening 53 while the liquid level would rise; however said meansare well known in the art and therefore will not further described.

A drawback that can be experienced during the working of a refrigerationapparatus as described refers to the evacuation rate of the box 5 andespecially to the air suction in the bag as previously described; saiddrawback is due to the fact that the vacuum pump has to be necessarilysized in the volume and in the produced noise, and so its suctionability must be limited and as a results this increases the timerequested for the vacuum done.

Furthermore it has to be considered that if the drawer 6 is notevacuated in a very short time and if the gasket 22 is not perfectlyclosed when the air is not yet fully drawn out of the box 5, then it mayeasily happen that the hermetic sealing of the gasket 22 and so thedesired vacuum condition may be prevented, due to the lack of theatmospheric pressure on the outside surface of the front door 10.

An advantageous solution to said problem is now given. With reference toFIG. 9, to the refrigerating apparatus according to the invention isassociated a buffer vacuum tank 25, i.e. an hermetic chamber that isinserted in the pipe connecting the vacuum box 5 to the vacuum pump 7.Furthermore, a control valve 28 is positioned between the vacuum box 5and the buffer vacuum tank 25, while said vacuum valve 13 is arrangedbetween the buffer vacuum tank 25 and the vacuum pump 7.

Said valves 13 and 28 are connected and controlled by said control meansmentioned before (FIG. 2), so accomplished and connected in order topermit their functioning according to the following procedure:

-   -   1. At the beginning and in stationary condition both valves 13        and 28 are open, the drawer 6 is closed into its box 5 and both        of them are under vacuum conditions; successively the drawer 6        is opened (pulled) so as to activate said switch 19 (or 19A);    -   2. The electric signal coming from said switch 19 is send to        said control means, that works out said signal and sends a        closing signal to the control valve 28, that immediately closes,        so cutting off said buffer tank 25 from said box 5;    -   3. After having been used, said drawer 6 is re-inserted in the        box 5 and the switch 19 is again activated;    -   4. Following said operation the control means 30 send a proper        signal to said control valve 28, so that it is immediately        opened;    -   5. As a consequence the air contained in the drawer 6 is        automatically drawn out from the vacuum existing in said buffer        tank 25, and the fact creates an immediate depression in the        drawer 6, so helping the hermetic closing of the same drawer, so        achieving the desired purpose.

Of course the same activation of the switch 19 makes the vacuum pump 7also to operate, according to the disclosed procedure.

1. A refrigerator and/or a freezer apparatus comprising a cabinet (1)with at least a compartment (2, 3) to store food, a box (5) firmlylodged in said compartment and closable in a vacuum-tight manner, adrawer (6) able to be extracted and inserted in said box, a vacuum pump(7) connected with a pipe (8) in a known way to a proper portion of saidbox and a vacuum valve (13) able to selectively equalise the internalpressure in said box, characterised in that said drawer comprises afront wall (10), and locking means (15-18) able to connect or disconnectsaid drawer to/from said box, said locking means including a movablehandle (15) pivoted in the front side of said drawer on pins (16) placedon opposed sides thereof.
 2. An apparatus according to claim 1,characterised in that said vacuum valve (13) and/or said vacuum pump (7)are operated by a tilting movement or by a horizontal movement of saidhandle (15).
 3. An apparatus according to 1 or 2, characterised in thatsaid vacuum pump (7) and/or said vacuum valve (13) are operated by theclosing movement of said drawer (6) into said box (5).
 4. An apparatusaccording to any of the preceding claims, characterised in that saidhandle comprises an extension link (17), and that said box comprisesengagements means (18), said extension link and said engagement meansbeing able to be connected and disconnected with the operation of saidhandle (15).
 5. An apparatus according to any of the preceding claims,characterised in that one or more electrical switches (19,19A) areplaced outside said box, said switches being able to be activated bysaid extension link (17) when said drawer (6) is closed into said box(5).
 6. An apparatus according to any of the preceding claims,characterised in that one or more electrical switches (19A) are placedoutside said box, said switches being able to be activated by the thrustof members (10, 12) of said drawer (6) when the same is closed into saidbox (5).
 7. An apparatus according to any of the preceding claimscharacterised in that one or more of said electrical switches (19,19A)are connected to said vacuum pump (7) and/or said vacuum valve (13). 8.An apparatus according to any of the preceding claims, characterised inthat a sealing gasket (14) is provided between the outer edge (11) ofsaid box (5) and the corresponding back surface (12) of the frontclosing wall (10) of said drawer (6).
 9. An apparatus according to anyof the preceding claims, characterised in that in standing conditions,i.e. vacuum pump stopped, box (5) evacuated, and drawer (6) closedinside said box (5), the vacuum valve (13) is operated in order to letoutside air enters into said box (5) and then to close the air flow fromoutside to said box, the vacuum pump (7) is activated in order to createvacuum conditions inside said box (5).
 10. An apparatus according to anyof the preceding claims, characterised in that it comprises a wall (40)on which a dispenser (41) is applied, said dispenser consisting of aprolonged member provided with an hollow conduit (42), open to outsidewith a mouth (43) and to the opposite side with a respective inner mouth(44), which is apt to be hermetically connected to a duct (46) leadingto a buffer tank (25).
 11. An apparatus according to claim 10,characterised in that said dispenser (41) is pivotally mounted to saidwall (40) by means of an hinge element (45), and that said hollowconduit (42) is connected to said duct (46) only when said dispenser isplaced in a selected position.
 12. An apparatus according to claim 10,characterised in that said dispenser is mounted so that said hollowconduit is connected to said duct only when the dispenser in forced inone direction in parallel with the airflow.
 13. An apparatus accordingto any of the claims 10-12, characterised in that it is provided with aliquid trap comprising a container (51) having first and second openings(52, 53) at different levels, said first opening (52) being connected tothe part of said duct (46) bound to said dispenser (41), said secondopening (53) being connected to said buffer tank (25).
 14. An apparatusaccording to claim 13, characterised in that a second valve (55) isprovided inside said container (51) and close to said second opening(53), so arranged that it closes said second opening when the liquidlevel inside said container reaches the level of said second opening.15. An apparatus according to any of the preceding claims, characterisedin that a control valve (28) is placed in the pipe connecting saidbuffer tank (25) to said box (5).
 16. An apparatus according to any ofthe preceding claims, characterised in that control means (30) areconnected to said vacuum valve (13), said vacuum pump (7), said controlvalve (28) and said switch (19,19A).